1. Field of the Invention
This invention relates to a copy medium feeding device in a copying machine or the like which may be loaded with a plurality of types of copy mediums at a time.
2. Description of the Prior Art
Recently, in the field of copying machines or the like, there has arisen a need to enable copy mediums of different sizes, colors and qualities to be properly used to enhance the efficiency of office work. With the conventional copying machines or the like, however, it has usually been the case that a single feeding table (on which the copy mediums to be fed are placed) and the feeding device of this type has been very inefficient in that when copy mediums of different sizes, colors and qualities are used, these copy mediums on the feeding table must be newly set each time.
The cassette type feeding system has been proposed to enable quick interchange between different copy mediums. According to this system, various types of copy mediums are respectively contained in exclusive cassettes (which are box-shaped containers formed with a port for setting or feeding copy mediums therethrough) and such cassettes may be loaded on the copy medium feeding station of the copying machine or the like, as required. This system eliminates the trouble to newly set the copy mediums each time copy medium interchange is effected, but it still involves the need to remove the presently loaded cassette and replace it by another desired cassette. In addition, such system requires the space available for unused cassettes and involves the necessity of cassette loading, which in turn requires the user to be cautious in handling the cassettes. Thus, this system is still left to be improved in many points.
In an effort to eliminate these inconveniences, the double cassette system has been put into practice which always permits two cassettes to be mounted on the copying machine or the like. According to this system, two different types of copy mediums to be used are respectively contained in two cassettes in advance, and these two cassettes are loaded onto the copying machine or the like. Thus, the copy mediums may be selectively fed through a single operation such as depression of a change-over button on the operating panel of the copying machine or the like.
However, as the customer's requirement has become more and more sophisticated, there has arisen a need for copying machines or the like which will permit three or four different types of copy mediums to be selectively used, namely, which will permit the use, in combination, of not only two different sizes of copy mediums but also one or more different qualities of copy mediums (for example, tracing paper used as the stencil paper for diazo copies).
It would be possible to adapt the construction of the double cassette system for use in such a case by increasing the number of the cassettes, but this would still encounter some disadvantages in practice as will hereinafter be discussed.
Generally, the cassette type feeding device is divided into a cassette section and a feeding section, and this feeding section comprises feed means for feeding copy mediums, guide means for guiding the copy mediums to a subsequent step of process, control means for intermittently causing the feed means to act on the copy mediums, etc. Thus, the conventional double cassette system may generally be grouped into the following two types of construction.
(1) Feed Operation Selection Type
Distinct cassettes are loaded onto two independent feeding sections and the feed means may act on a selected one of the feeding sections to feed selected copy mediums from that cassette. This has widely been put into practice.
(2) Cassette Position Change-over Type
Two cassettes are disposed in a single feeding section and at the positions where the cassettes may be changed over. Each cassette may be displaced to assume the same relative position with respect to the same feed means, thereby feeding copy mediums. This has not widely been put into practice.
In the feed operation selection type which has two independent feed means provided in two steps, the change-over between the two feed means may be accomplished by electrical control and if required at all, by a very simple change-over mechanism, but this type requires a space substantially double that of a single feed means, the ratio of the distances being 2:1 as will be seen in FIG. 1 of the accompanying drawings.
Thus, provision of three or four feed means for a single machine would mean the necessity of increasing the space to three or four times and this is structurally undesirable. If unreasonable efforts were made to reduce the space by extremely reducing the number of copy mediums to be contained per cassette (usually, at least about 250 sheets is necessary), there would still remain the problem that the guide means for guiding the copy mediums to the subsequent step of process would become complicated and thus, it would almost impossible to realize a desk-top type copying machine (usually with a height of 40 cm or less).
On the other hand, the cassette position change-over type, as shown in FIG. 2 of the accompanying drawings, would be advantageous in respect of the required space inasmuch as the space would only be increased at a rate of approximately 40 to 50% of one feed means even if the number of the cassettes were increased. However, because of the need to displace the cassettes, the change-over of the cassettes would involve the necessity for a change-over mechanism in addition to the electrical control.
Therefore, displacing three or four cassettes to their respective predetermined positions and fixing them thereat would require a complicated and large-scale mechanism, which would accordingly lead to complication of the electrical control.